Hey, On Mon, Mar 19, 2018 at 04:57:45PM +0000, Bart Van Assche wrote: > For synchronization primitives that wait having a stronger synchronization > primitive nested inside a more relaxed one can lead to a deadlock. But since > the rcu read lock primitives do not wait it could be safe to use that kind > of nesting with RCU. Do you perhaps know whether any documentation is > available about that kind of nesting or whether it is already used elsewhere > in the kernel? Oh, we nest them all the time. They're like (and sometimes literally are) preempt_disable() and don't care about nest ordering. Thanks. -- tejun